I do not use MDF as a construction material, this is due to its poor painting values, long term strength and hazardous vapours/fibres given off during cutting.

As an alternative I use laminated birch ply sheeting that can be either sanded to give a smooth paintable finish or left natural natural to give a visible grain once painted. This sheeting will give a far better finish when routered and give a better overall strength for little extra cost.